AHA’s, BHA’s, Azelaic Acid, Retinol, Vit C

What are Alpha Hydroxy Acids (AHAs) and where do they primarily work in the skin?

They are water-soluble exfoliating acids that dissolve in water and primarily work within the skin's water-rich layers.

How do glycolic, lactic, and mandelic acids compare in terms of molecular size?

Glycolic acid is the smallest molecule, lactic acid is the middle size, and mandelic acid is the largest molecule.

What are the primary characteristics and skin benefits of glycolic acid?

Glycolic acid is the smallest and most potent AHA, penetrates the deepest, supports the dermis, and is best for aging.

What is lactic acid derived from and what primary benefit does it offer?

Lactic acid is derived from milk and helps mostly with brightening.

What is the molecular weight of lactic acid and what dual action does it perform on the skin?

Lactic acid has a molecular weight of $90$. It functions both as a chemical exfoliant (breaking down corneodesmosomes) and as a great hydrating humectant.

What are the three sequential steps of lactic acid's action on the skin?

1. Penetrates Stratum Corneum.
2. Loosens desmosomes between corneocytes.
3. Allows dead surface cells to shed more easily.

How do Natural Moisturizing Factors (NMFs) function when stimulated by lactic acid?

NMFs are small molecules acting like a built-in hydration system that attract and hold water to keep the Stratum Corneum hydrated and plump.

What is the molecular weight of mandelic acid and what was it originally derived from?

Mandelic acid has a molecular weight of $152\,g/mol$ and was originally derived from bitter almonds.

Why is mandelic acid considered the gentlest AHA and recommended for sensitive skin?

It has a relatively large molecular weight and the slowest penetration speed out of all AHAs commonly used in skincare.

How does mandelic acid exfoliate the skin and treat hyperpigmentation?

It weakens the bonds holding dead skin cells together to shed evenly through desquamation, prevents clogged pores, and accelerates cell turnover to gradually fade hyperpigmentation.

What additional properties make mandelic acid particularly beneficial for congestion and acne-prone skin?

It has antibacterial and anti-inflammatory properties.

Does Azelaic Acid belong to the AHA or BHA family of skincare acids?

No, Azelaic Acid does not belong to any AHA or BHA family; it is considered its own class of skincare.

What is the molecular weight of Azelaic Acid, and how does its molecular size affect skin diffusion and irritation?

Azelaic Acid has a molecular weight of $188\,g\,mol^{-1}$. Because its molecular size is relatively large, it diffuses through the skin slower, making it less irritating than other acids.

What does it mean that Azelaic Acid is amphiphilic, and why is formulation critical?

Amphiphilic means it is both water and oil soluble. However, because it does not dissolve particularly well in either by itself, formulation matters significantly.

What are the five main benefits of Azelaic Acid listed in order?

1. Reduces inflammation, 2. Normalises Keritinisation, 3. Antimicrobial activity, 4. Reduces pigmentation, 5. Improves PIE.

How is Vitamin A categorized in terms of solubility?

Vitamin A is a fat-soluble vitamin that is lipophilic (oil soluble).

What are retinoids, and what is their active end point?

Retinoids are a family of Vitamin A compounds that can influence how skin cells behave, and Retinoic acid is their active end point.

How many oxidation steps do Retinol and Retinal need to become retinoic acid?

Retinol needs 2 oxidation steps before becoming retinoic acid, whereas Retinal needs only 1 oxidation step.

What is Tretinoin composed of?

Tretinoin is all retinoic acid.

What are the four primary benefits of Retinoids?

1. Normalises Keritinisation, 2. Treats inflammatory acne, 3. Improves photoaging, 4. Improves pigmentation & uneven skin tone.

What is another name for Vitamin C, and what is its solubility?

Vitamin C is also called Ascorbic Acid, and it is a water-soluble vitamin.

What are the main roles of Vitamin C in skincare?

Its main roles are antioxidant protection, collagen synthesis, brightening pigment, and inflammatory effects.

What type of acid is Salicylic Acid, and where is it naturally derived from?

Salicylic Acid is a Beta Hydroxy Acid naturally derived from willow bark, though it is almost always made in a lab for purity.

What does it mean that Salicylic Acid is lipophilic?

It means Salicylic Acid is oil soluble, allowing it to be pulled and naturally drawn into oily environments like pores where congestion starts.

How do blackheads, whiteheads, and pore congestion form?

When dead skin cells do not shed properly during desquamation, they stick together and mix with sebum to form a plug inside the pore, creating congestion.

What specific structures does Salicylic Acid target and loosen to allow skin shedding?

Salicylic Acid loosens corneodesmosomes, which act like rivets or bonds holding dead skin cells together, allowing the skin's natural desquamation process to proceed.

Which skin conditions make a person a perfect candidate for Salicylic Acid?

Blackheads, whiteheads, oily skin, and congestion.

What are the five protocol questions to assess before using Salicylic Acid on a client?

1. What condition is the skin barrier in? 2. What is the client's skin type? 3. How resilient is their skin? 4. What supporting ingredients would benefit them? 5. What formulation is it? (Alcohol? encapsulated)