About 24 people attended. 

Here's an overview of what was presented:

The material is not intended to diagnose, treat, cure, or prevent disease or replace professional medical care.

II. Alpha hydroxy acids (AHAs): surface exfoliation

AHAs remove dead surface cells and may improve brightness, softness, texture, fine lines, sun damage, and uneven tone.

1. Glycolic acid

   • Strong, commonly used AHA.

   • Penetrates readily because of its small molecular size.

   • May help rough texture, fine lines, discoloration, and sun-damaged skin.

   • Has a moderate-to-high irritation potential.

2. Lactic acid

   • Gentler than glycolic acid.

   • Provides exfoliation along with hydration.

   • Often suited to dry, mature, or somewhat sensitive skin.

   • Has a low-to-moderate irritation potential.

3. Mandelic acid

   • Has a larger molecular structure and penetrates more slowly.

   • Often better tolerated by sensitive or acne-prone skin.

   • May help uneven skin tone.

   • Has a relatively low irritation potential.

III. Beta hydroxy acid (BHA): pore-clearing

1. Salicylic acid

   • Oil-soluble, allowing it to penetrate oily pores.

   • May help blackheads, whiteheads, acne, and excess oil.

   • Can also reduce inflammation.

   • Has a moderate irritation potential.

IV. Polyhydroxy acids (PHAs): gentle exfoliation

PHAs have larger molecules than AHAs, so they generally penetrate more slowly and cause less irritation.

1. Gluconolactone

   • Provides gentle exfoliation and antioxidant support.

   • Often appropriate for sensitive or reactive skin.

   • Has very low irritation potential.

2. Lactobionic acid

   • Supports hydration and gentle resurfacing.

   • Often used for dry, sensitive, or mature skin.

   • Has very low irritation potential.

V. Hydrating acids and related ingredients

These ingredients are not primarily exfoliants.

1. Hyaluronic acid

   • Attracts and retains water in the skin.

   • May improve dryness and temporarily increase a plump appearance.

   • Usually tolerated by most skin types.

   • Has very low irritation potential.

2. Pantothenic acid, or vitamin B5

   • Commonly appears on product labels as panthenol.

   • Helps support the skin barrier, hydration, and soothing.

   • Often pairs well with hyaluronic acid, niacinamide, peptides, and exfoliating acids.

   • Has very low irritation potential.

VI. Acne- and redness-focused acid

1. Azelaic acid

   • May help acne, redness, rosacea-like irritation, dark spots, and uneven pigmentation.

   • Usually gentler than many traditional exfoliating acids.

   • Has a low-to-moderate irritation potential.

VII. Vitamin C acid

1. Ascorbic acid

   • Functions as an antioxidant.

   • May support collagen production and brighten dull or sun-damaged skin.

   • Can sting or irritate sensitive skin.

   • Has a low-to-moderate irritation potential.

VIII. Main comparison points

The presentation compares the acids according to:

• Chemical category

• Primary skincare purpose

• Skin types or concerns for which they may be best suited

• Relative irritation potential

IX. Central takeaway

Different acids serve different purposes:

• For stronger surface exfoliation: glycolic acid

• For gentler exfoliation and hydration: lactic acid

• For sensitive or acne-prone skin: mandelic acid

• For oily pores and blackheads: salicylic acid

• For very sensitive or mature skin: PHAs

• For hydration: hyaluronic acid and vitamin B5

• For redness, acne, and pigmentation: azelaic acid

• For antioxidant and brightening benefits: ascorbic acid