Why skin gets oily
Sebum production is driven primarily by sebaceous glands under the influence of androgens. Genetics, hormones, and age all affect baseline sebum output. In humid climates, high ambient temperature increases sebaceous gland activity on top of the genetic baseline, which is why people who were mildly oily in a cooler country often find their skin becomes significantly more oily after relocating to Singapore, Malaysia, or a similarly humid region.
Oiliness peaks in adolescence and the twenties, then tends to decline. But in the humid tropics, the climate compensates -- many people in their thirties and forties remain significantly oily year-round.
The most common mistake for oily skin is using harsh, stripping cleansers multiple times a day to remove shine. When the skin surface is stripped of its natural oil layer, the skin registers a deficit and triggers more sebum production to compensate. The result is skin that feels clean for 30 minutes, then becomes even oilier than before. Mild cleansers used twice daily are more effective at managing oiliness long-term than frequent harsh cleansing.
Pores: what you can and cannot change
Pore size is largely genetic. The appearance of enlarged pores is influenced by sebum content (full pores appear larger), sun damage (UV degrades the collagen supporting pore walls), and age (skin loses elasticity over time, allowing pores to look more open). You cannot physically shrink pores, but you can influence their visible appearance:
- Regular gentle exfoliation (especially BHA) keeps pores clearer and reduces the appearance of congestion
- Niacinamide is commonly used to reduce the visible appearance of pores over time
- Daily SPF protects the collagen framework that keeps pore walls firm
- Some primers and blurring products cosmetically minimise the appearance of pores temporarily
Sebaceous filaments vs blackheads
This distinction is genuinely useful and frequently missed. The grey or beige plugs visible on the nose and cheeks of most people are sebaceous filaments -- natural tube-like structures that line oil ducts and help deliver sebum to the skin surface. They are a normal part of skin anatomy, not a sign of congested or dirty skin.
True blackheads (open comedones) are oxidised plugs of sebum and dead skin cells that have formed a dark cap. They typically feel slightly raised, have a visible dark top, and can be extracted. Sebaceous filaments refill quickly after extraction because they are structural, not a blockage -- which is why nose strips and extractions on sebaceous filaments produce no lasting result.
Managing sebaceous filaments means keeping them clear with regular BHA use, not trying to eliminate them.
Ingredients commonly used for oily skin management
Niacinamide
Niacinamide at 5-10% concentrations is widely used for regulating sebum production, minimising the appearance of pores, and improving skin texture. It is well-tolerated, Malassezia-safe, and compatible with most other ingredients. Evidence for sebum regulation is reasonable, though effects are gradual and take 8-12 weeks to show clearly.
Salicylic acid (BHA)
Beta hydroxy acid is oil-soluble, meaning it can penetrate the inside of oil-filled pores to dissolve sebum and dead cell buildup. It is one of the most evidence-backed ingredients for comedonal acne and pore congestion. A 0.5-2% salicylic acid toner or serum used 2-3 times per week is a common starting approach for oily and congested skin.
Clay (kaolin, bentonite)
Clay masks are commonly used to absorb excess sebum from the skin surface. The effect is temporary (oil returns as sebum is produced), but they can help manage the sensation and appearance of oiliness. Limit clay masks to 1-2 times per week -- daily use over-dries the skin and can trigger compensatory oiliness.
Lightweight textures
For oily skin in humid climates, texture matters as much as ingredient. Gels, gel-creams, and fluid formulations layer without adding occlusion. Rich creams and heavy emollients trap heat against the skin and increase oiliness. This applies to moisturisers, SPF, and serums.
Oily skin still needs hydration -- water, not oil. Skipping moisturiser on oily skin often leads to dehydrated-but-oily skin, a combination that is harder to manage. Use a light, water-based gel moisturiser with glycerin or hyaluronic acid rather than skipping the step entirely. See the dehydrated skin guide for more on this distinction.
When to think about other possibilities
If your skin has become suddenly oilier or if standard oily skin management is not helping, consider whether fungal acne or dehydration may be part of the picture. Dehydrated skin can present as oily because the disrupted barrier triggers compensatory sebum production. Malassezia folliculitis on oily skin is also common in humid climates.