Comes in two forms, Retinoic acid which is the absorbable form and is the component of medical strength or prescription Vit A (eg RetrieveÒ/DifferinÒ) or Retinol which is in the over the counter products - 2-3% of retinol is converted to retinoic acid in the skin.
Using it at night, it increases cell turnover, stimulates collagen and blood flow so becomes a powerful antiaging tool, thickening and plumping the skin, decreasing wrinkles, pigmentation, pore size and pimples – yes it really is a vital part of skin care.
It shouldn’t be used in pregnancy and it can cause skin irritation. This can usually be overcome though by starting with a very small amount and only using it at night once a week to start and gradually build up to daily over a month or so.
Sometimes diluting with a bland moisturiser to begin with also helps you avoid irritation, it is worth trying to persist with it as the benefits are enormous.
The active form of B3 is called Niacinamide. It increases the barrier function of the skin by increasing ceramides and this means the skin tolerates other things such as Vit A better.
It can be used once or twice a day.
It is anti-inflammatory so can really help conditions such as rosacea and acne. It also helps decrease pigmentation and can help decrease the rate of development of some skin cancers. It can be taken twice a day orally as well.
This is vital for collagen and elastin production. It is a powerful antioxidant and acts as a free radical scavenger - free radicals can damage DNA and the resultant skin damage can lead to aging and skin cancers. It is best used in the morning, so it is available to do this while we are exposed to UV light and pollutants, in conjunction with sunscreen.
As an extra, it can be used at night also.
Vit C also helps decrease the activity of cells that produce pigment and is often used in conjunction with skin bleaches such as hydroquinone in treating pigmentary problems like melasma.
One problem with Vit C is that it’s very acidic and this can cause irritation for some. Some formulations of Vit C are better kept in the dark and relative cool to keep them active.
Alphahydroxy acids are naturally occurring fruit acids seen in a range of skin products. They are water soluble and in low concentrations act as humectants or moisturisers.
In higher concentrations they are exfoliants and can be used as creams/serums or in facial peels.
The commonest ones are Glycolic acid (from sugar cane), Lactic acid (milk) and Mandelic acid (bitter almonds)
Glycolic acid has the smallest molecules and is able to penetrate the skin the deepest so can be quite strong and irritating. Lactic acid has a bigger molecule so penetrates the skin to a lesser extent and is more gentle. Mandelic acid has the largest molecule and is thus the least penetrating and the most gentle - it can have a place in sensitive skins and is also safe in pregnancy. It can also be good in melasma / hyperpigmentation as it tends not to cause irritation, which can aggravate pigment.
As exfoliants, AHA’s chemically get rid of dead skin cells, increasing cell turnover and encouraging new cells to grow so the skin feels softer as barriers are repaired. This is another powerful antiaging tool, with added benefits of decreasing pore size and pigmentation.
AHA’s are also very useful in keratosis pillaris which causes red, lumpy skin on the upper arms or legs often seen in teenagers.
BHA’s- betahydroxy acids are lipophilic so like oil and these can be very useful in acne and controlling oil production/pores.