Good question — the “best” deodorant depends on his body chemistry, activity level, skin sensitivity, and whether you want an antiperspirant (reduces sweat) or a deodorant (controls odor only). Here’s a short, practical guide plus specific suggestions to try.

Quick primer

• Antiperspirant (contains aluminum): reduces sweating — good for active teens or heavy sweaters. Apply at night for best effect.
• Deodorant (no aluminum): prevents odor but doesn’t stop sweat — good if you prefer “natural” products or want to avoid aluminum.
• Fragrance-free / hypoallergenic: choose if he has sensitive skin or irritation.
• Clinical‑strength: for very heavy sweating (hyperhidrosis) — use only as directed and consider a doctor if it’s severe.
• Natural options: plant/ baking‑soda based — gentler for some, but can irritate others.

Practical pick suggestions (widely used, good starting points)

• For everyday sporty teens who sweat a lot: Degree Men / Degree Sport (antiperspirant) or Old Spice Clinical (antiperspirant/clinical strength) — strong sweat control and long‑lasting.
• For sensitive skin: Dove Men+Care Fragrance‑Free or Dove Advanced Care — moisturizing, less irritating.
• For body‑odor control with milder sweat: Old Spice or Axe deodorants (many scents teens like).
• For natural/deodorant‑only: Native, Schmidt’s, or Tom’s of Maine — look for baking‑soda free versions if he’s sensitive.
• For heavy sweating / clinical strength: Certain Dri or clinical formulas like Certain Dri Extra Strength (follow label; consult a doctor if needed).
• Budget option that works well: Arm & Hammer (odor control with baking soda) or Mitchum (good sweat control).

How to choose and use

1. Start with an antiperspirant if he’s active or has noticeable sweat stains/odor.
2. If skin gets red/itchy, switch to fragrance‑free/hypoallergenic or a natural option.
3. Teach application: apply to clean, dry underarms. Antiperspirants work best at night (applied to dry skin) because they block sweat glands while you sleep. Reapply in the morning if it’s a deodorant-only product.
4. If deodorant stains shirts, try a clear/gel formula or apply less product and let it dry before dressing.
5. If he has persistent strong odor, irritation, or very heavy sweating despite OTC products, see a pediatrician/dermatologist.

If you want, tell me: his age, whether he’s very active/sports, any skin sensitivity, or whether you prefer natural products — I’ll pick 2–3 specific products to try.