Adult acne: cause and treatment

The prevalence of adult acne is soaring. Dermatological studies suggest up to 54% of adult women and 40% of adult men present with some form of facial acne, with 12% of adult women presenting with fully diagnosable clinical adult acne1. The condition can be embarrassing, frustrating and for many, it can feel never ending.

Adult acne does not just affect a person’s skin; it also significantly impacts emotional well-being. A condition usually experienced during teenage years, experiencing acne later in life is directly linked to an increase in depression and anxiety2. Rates of depression rank three times higher in portions of the population suffering from acne3.

Statistics like these are awakening. Adult acne is not just a dermatological disorder, it also has a significant impact on a person’s mental well-being. Noticeably rates of adult acne are rising considerably – a rise seemingly unique to the Western Hemisphere. While adolescent acne is induced by rapid changes in a person’s sex hormones, adult acne being a post-adolescent form of the condition is not caused by the same provocation. Puberty has passed, so why is this teenage skin disorder now affecting adults?

To help you understand and counteract the causes of adult acne we’ve prepared this adult acne guide. With almost a 50% chance any individual will experience adult acne during their lifetime – everyone should be armed with the understanding of its causes and countering available treatments.

Cause of adult acne: High glycaemic index diets

The correlation between a Western lifestyle and rise in adult acne has shone light on the western diet. Is it to blame for the steep rise in this troublesome skin disease? Many dermatologists say yes. While there are marked variations in cuisine, there’s one over-arching dietary difference. If a person eats in the West, they are likely to have a high percentage of refined and high GI foods in their diet. If a person eats in the East, their diet has very few of these foods.

The glycaemic index is a measure of the speed by which a food is broken down into blood sugar. Ultimately all foods are processed by the body to supply energy as blood sugar, the distinction is in how quickly each food allows this to occur. Foods with a high GI are broken down into blood glucose rapidly, supplying a quick energy spike. Foods with a low GI are broken down into blood glucose gradually, supplying a sustained energy release.

Quick spikes in blood sugar provoke the release of a hormone called insulin. With insulin release come several accompanying hormones – one of which goes by the name of insulin-like growth factor (IGF-1). Studies show that levels of IGF-1 are significantly increased in patients with post-adolescent acne4. Insulin and IGF-1 stimulate skin’s rate of sebum production5 – a pivotal factor in the acne causation triangle.

The pathology of adult acne relies on 3 factors – increased sebum production, dead skin and bacteria (p.acnes). Adult acne is provoked when plugs of sebum trap dead skin cells within hair follicles – these plugs then provide food to bacteria normally present on the surface of the skin, of which one kind, p.acnes secretes an inflammatory compound as a by-product of its metabolism.

Reduce your risk or incidence of adult acne by following a low GI diet

Control of blood glucose levels has several health benefits for an individual, including the treatment and prevention of adult acne. Low GI diets prevent spikes in blood sugar, preventing insulin and IGF-1 release and therefore reducing sebum production. Following a low GI diet involves identifying and removing high GI food groups. The most common example of which are;

  • White bread (baguettes, bagels)
  • Cakes and patisseries (doughnuts, cupcakes, croissants)
  • Energy drinks (Lucozade, Sports plus, Gatorade)
  • Crisps
  • Sweets
  • Certain fruits (bananas, watermelon, raisins)
  • Some cereals (Cheerio’s, Rice Krispies, Cornflakes)6

Not all high GI foods are obviously unhealthy – certain whole foods such as bananas also provoke large increases in blood sugar levels. Use this GI table to help modify your diet.

Cause of adult acne: Dairy

Many forms of dairy, especially low-fat alternatives rate highly on the GI scale, however, this food groups adult acne impact is three-fold;

  1. Dairy is a high GI food causing release of insulin + IGF-1
  2. Dairy contains hormones – providing young mammals with the nutrients needed to grow quickly
  3. Dairy contains a protein which is able to cause inflammation in many people – B-casein – type A1

Dairy and foods containing dairy e.g. milk chocolate, cereal bars and biscuits also contain portions of hormones. Milk is highly nutrient dense because its purpose is to ensure the successful growth of young humans into healthy adults. The same is true for cow’s milk, however, its purpose is to grow young calves into healthy adults. While adolescent acne is caused by the systemic release of sex hormones, studies propose adult acne is provoked by external intake of hormone-rich foods such as dairy7.

Dairy also contains a suspect protein – type A1 b-casein. In many people, this protein is broken down within the digestive tract to β-casomorphin-78. An inflammatory morphine which activates a person’s immune function causing ongoing stress and system-wide inflammation. Adult acne is characterised as being a chronic inflammatory condition. Therefore foods that cause inflammation worsen acne. The proteins found in cow milk are also directly linked to the synthesis of IGF-19, a stimulant of sebum production.

Reduce your risk or incidence of adult acne by avoiding dairy

Only in recent history has dairy become a common staple in western diets. Before the evolution of industrial farming, dairy was consumed only by infants to help stimulate their growth. In the twentieth century dairy is now not only present in most adult diets, it’s also added to many pre-made foods.

Dairy elimination should be trialled for 2-4 weeks and the effects monitored. Full elimination requires careful examination of food labels, pre-made foods such as guacamole, gnocchi, and ravioli commonly contain dairy-based ingredients.

Cause of adult acne: Comedogenic skincare

Adult acne is caused as a consequence of blocked hair follicles, an event which can be provoked by the use of comedogenic skin care. Comedogenicity refers to the ability of individual skincare ingredients to block a person’s pores. If ingredients have a very small molecular size, they are easily washed in and out. If ingredients have a molecular size larger than a person’s pores, they will calmly sit on top of the skin. If skincare ingredients have a molecular size very similar to a person’s pore size, they are likely to become trapped within pores, being unable to wash out.

The comedogenicity scale runs from zero to five with zero rated as no comedogenicity and five rated as high comedogenicity. Skincare ingredients with high comedogenicity are best avoided for skin types prone to adult acne. The likelihood of skin care preparations such as moisturisers and serums to cause adult acne or acne cosmetica depends on a number of comedogenic ingredients used – if comedogenic ingredients are low on the ingredients list, their effects are diluted10.

Reduce your risk or incidence of adult acne by avoiding comedogenic skin care

By law, all skincare products must make available their full ingredients lists. These lists helpfully follow a set of rules defining that ingredients must be ordered in decreasing quantity until the 1% line after which skin care ingredients may be reported in any order.

Comedogenicity studies show the following ingredients have high pore blocking potential11, 12;

  • Acetylated lanolin alcohol (4-5)
  • Cetearyl alcohol + ceteareth-20 (4)
  • Cetyl acetate (4)
  • Cocoa butter (4)
  • Coconut butter (4)
  • Ethylhexyl palmitate (4)
  • Glyceryl-3-diisostearate (4)
  • Isocetyl alcohol (4)
  • Isopropyl isostearate (4-5)
  • Isopropyl linoleate (4-5)
  • Isopropyl myristate (5)
  • Isostearyl isostearate (4)
  • Lanolin acid (4)
  • Laureth-4 (5)
  • Lauric acid (4)
  • Myristyl lactate (4)
  • Myristyl myristate (5)
  • Oleth-3 (5)
  • Oleyl alcohol (4)
  • PEG-16 lanolin (4)
  • Polyglyceryl-3-diisostearate (4)
  • PPG-5 ceteth-10 phosphate (4)
  • Steareth-10 (4)
  • Stearyl heptanoate (4)
  • Xylene (4)

To reduce the risk and incidence of adult acne, a skincare regimen should be full of skincare products low in highly comedogenic ingredients. If ingredients rated as 4 or 5 on the comedogenicity scale are high on the ingredients list, the product in question should be avoided, if ingredients high in comedogenicity are low on the ingredients list, the product in question is likely appropriate for acne-prone skin.

Cause of adult acne: Lipid oxidation

All skin types produce sebum however oily and combination skin types produce a much greater rate than normal. Sebum is a complex mixture of fatty acids, ceramides, and cholesterol. Squalene is prevalent in sebum at a quantity of around 12%13. The molecular structure of squalene makes it vulnerable to oxidative attack. When squalene oxidises it forms squalene peroxide an oxidative compound that depletes skin of vitally defensive antioxidants such as vitamin E. Studies show that adult acne patients have a significantly lower level of vitamin E than non-sufferers14. The formation of oxidation by-products causes assault to the skin resulting in inflammation15 – a cause of adult acne.

Reduce your risk or incidence of adult acne by using antioxidant rich skincare

Lipid peroxidation can be both halted and compensated for through the use of appropriate skin care. To help halt the oxidation of sebum, sunscreen should be applied daily. UV light is a well-known oxidant and studies show it to be directly responsible for the depletion of squalene and creation of squalene peroxide16. Daily application of sunscreen helps to prevent lipid peroxidation caused by UV light.

starter-kit

To help defend against the antioxidant depletion lipid peroxides cause, antioxidant serums and moisturisers should be used regularly. Products such as our griffin+row Enrich – Antioxidant night cream help to replenish antioxidant skin reservoirs helping to resist future squalene peroxidation.

Cause of adult acne: Acid mantle impairment

Healthy skin types have a pH between 4.2-5.617 which rates as moderately acidic on the pH scale running from 0-14. An acidic pH is vital to a healthy skin type, technically called skin’s acid mantle when pH strays outside of normal, skin becomes dehydrated, desquamation (natural exfoliation) is impaired, resident microflora populations become perturbed and pathogenic growth of bacteria ensues. The bacteria seen to grow in pathogenic proportions in acne patients – p.acnes, has an impaired growth at pH values below 5.5, however, growth is easily facilitated at pH values between 6-6.518. When skin’s acid mantle is tweaked towards an alkaline pH, acne causing bacteria thrive.

Reduce your risk or incidence of adult acne by following a balanced diet and healthy cleansing routine

Skin’s acid mantle is easily affected by skincare products. When skincare products with an alkaline pH are used, skin’s pH is temporarily perturbed. Changes to skin pH may last for hours, or with continued use of strong cleansing products, may become a persistent feature of a person’s skin condition. Traditionally used cleansing products such as bar soap, frequently have an alkaline pH. A recent review of marketed cleansing products showed some rate as highly as 1219 – an extremely alkaline pH.

starter-kit

To protect skin’s acid mantle and avoid the pathogenic growth of acne causing bacteria, strong cleansing products should be replaced with mild, sensitive skin friendly gels, creams, and oils. Products such as the griffin+row cleanse gel delicately cleanse skin while also helping to maintain a healthy pH balance.

In addition to skincare, diet has a great impact on skin health. The sebum composition of acne prone skin types is found to be deficient in a specific type of fatty acid – linoleic acid. This deficiency is linked to hyperkeratinisation and ineffective desquamation20. Re-introduction of linoleic acid applied topically has been shown to help reduce the size and severity of microcomedones21. This deficiency may in part be compensated for by adherence to a diet high in omega-3 and 6 fats. These can be found in foods such as fatty fish e.g. salmon and mackerel or ingested as a dietary supplement.

Cause of adult acne: Polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is estimated to affect between 8 to 20% of people at reproductive age, worldwide22. The condition roots from hormonal abnormality, specifically an increased production of male sex hormones – androgens. As is the cause of adolescent acne, this heightened production of androgens often leads to the PCOS side effect of acne. Androgens cause an increase in skin’s production of sebum, leading to the accumulation of sebum and dead skin cells within hair follicles which in turn propagates the acne causing bacteria – p.acnes. Both a number of androgens produced and a person’s sensitivity to androgen hormones effects the corresponding increase in sebum production23.

Reduce your risk or incidence of adult acne with regular exfoliation and spearmint tea

The pathology of acne relies on 3 central factors – increased sebum production, dead skin collection and the pathogenic grown of p.acnes. All 3 factors are dependently interlinked – without an increased sebum excretion dead skin cells may not congregate, without dead skin cells congregating, p.acnes bacteria may not proliferate.

starter-kit

Regular physical or chemical exfoliation helps to deplete the residence of dead skin cells, leading to a reduction of p.acnes growth and therefore a reduction of acne. Regular manual exfoliation can be integrated with products such as the griffin+row muslin cloth and regular chemical exfoliation can be integrated through products containing salicylic acid.

Recent studies also show promise for spearmint tea. A natural active with an investigated anti-androgenic effect. During trials, participants drank 2 spearmint teas daily for 30 days and as a result their androgen hormone levels significantly reduced24. An effect predicted to reverse androgen caused PCOS symptoms such as acne.


  1. Goulden  V,  McGeown  CH,  Cunliffe  WJ.  The  familial  risk  of  adult  acne:  a comparison between first-degree relatives of affected and unaffected individuals. Br J Dermatol 1999; 141: 297-300
  2. Clinical implications of lipid peroxidation in acne vulgaris: old wine in new bottles, A Bowe, Whitney P. A Logan, Alan C. J Lipids in Health and Disease Lipids in Health and Disease 2010 9: 141 DOI: 10.1186/1476-511X-9-141
  3. Uhlenhake E, Yentzer BA, Feldman SR: Acne vulgaris and depression: a retrospective examination. J Cosmet Dermatol. 2010, 9: 59-63. 10.1111/j.1473-2165.2010.00478.x
  4. Aizawa, H. and Niimura, M. (1995), Elevated Serum Insulin-like Growth Factor-1 (IGF-1) Levels in Women with Postadolescent Acne. The Journal of Dermatology, 22: 249–252. DOI:10.1111/j.1346-8138.1995.tb03381.x
  5. Smith TM, Gilliland K, Clawson GA, Thiboutot D. IGF-1 induces SREBP-1 expression and lipogenesis in SEB-1 sebocytes via activation of the Phosphoinositide 3-kinase (PI3-K)/Akt pathway. The Journal of investigative dermatology. 2008;128(5):1286-1293. DOI:10.1038/sj.jid.5701155.
  6. International table of glycemic index and glycemic load values: 2002. Kaye Foster-Powell, Susanna H. A. Holt, Janette C. Brand-Miller Am J Clin Nutr. 2002 Jul; 76(1): 5–56.
  7. Nutrition and acne Clinics in Dermatology, Volume 28, Issue 6, Pages 598-604 F. William DanbyJ Am Acad Dermatol. 2005 Feb; 52(2): 207–214. doi: 10.1016/j.jaad.2004.08.007
  8. Jianqin S, Leiming X, Lu X, Yelland GW, Ni J, Clarke AJ. Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows’ milk. Nutrition Journal. 2015;15:35. doi:10.1186/s12937-016-0147-z.
  9. Hoppe C, Molgaard C, Michaelsen KF. Cow’s milk and linear growth in industrialized and developing countries. Annu Rev Nutr 2006;26: 131-73.
  10. A re-evaluation of the comedogenicity concept. Zoe Diana Draelos, Joseph C. DiNardo J Am Acad Dermatol. 2006 Mar; 54(3): 507–512. doi: 10.1016/j.jaad.2005.11.1058
  11. JE Fulton, Comedogenicity and irritancy of commonly used ingredients in skin care products, J Soc Cosmet Chem 1989, 40, 321-333.
  12. WE Morris and SC Kwan, Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients, J Soc Cosmet Chem 1983, 34, 215-225.
  13. Picardo M, Ottaviani M, Camera E, Mastrofrancesco A. Sebaceous gland lipids. Dermato-endocrinology. 2009;1(2):68-71.
  14. Picardo M. Sebaceous gland lipids. 2nd International Conference “Sebaceous gland, acne, rosacea and related disorders Basic and clinical research, clinical entities and treatment”; 2008; Rome.
  15. Briganti, S. and Picardo, M. (2003), Antioxidant activity, lipid peroxidation and skin diseases. What’s new. Journal of the European Academy of Dermatology and Venereology, 17: 663–669. doi:10.1046/j.1468-3083.2003.00751.x
  16. Ultraviolet a induces generation of squalene monohydroperoxide isomers in human sebum and skin surface lipids in vitro and in vivo. Swarna Ekanayake Mudiyanselage, Matthias Hamburger, Peter Elsner, Jens J. Thiele J Invest Dermatol. 2003 Jun; 120(6): 915–922. DOI: 10.1046/j.1523-1747.2003.12233.x
  17. Blank HI, Measurement of pH of the skin surface. J lnvrsl Dermatol 1939;2:67-79.
  18. The effect of detergents on skin pH and its consequences. Korting HC, Braun-Falco O. Clin Dermatol. 1996 Jan-Feb;14(1):23-7. Review. No abstract available.
  19. Correlation between pH and irritant effect of cleansers marketed for dry skin. Baranda L, González-Amaro R, Torres-Alvarez B, Alvarez C, Ramírez V. Int J Dermatol. 2002 Aug;41(8):494-9.
  20. Essential fatty acids and acne. Downing DT, Stewart ME, Wertz PW, Strauss JS. J Am Acad Dermatol. 1986 Feb;14(2 Pt 1):221-5.
  21. LETAWE, BOONE and PIÉRARD (1998), Digital image analysis of the effect of topically applied linoleic acid on acne microcomedones. Clinical and Experimental Dermatology, 23: 56–58. doi:10.1046/j.1365-2230.1998.00315.x
  22. Sirmans, S. M., & Pate, K. A. (2014). Epidemiology, diagnosis, and management of polycystic ovary syndrome. Clinical Epidemiology, 6, 1–13.
  23. Hirsutism and acne in polycystic ovary syndrome. Archer JS, Chang RJ. Best Pract Res Clin Obstet Gynaecol. 2004 Oct;18(5):737-54. Review.
  24. Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome. A randomized controlled trial. Grant P. Phytother Res. 2010 Feb;24(2):186-8. doi: 10.1002/ptr.2900.