FAQ: Frequently Asked Questions

Arithmetic closed. Our products are no longer available.
Who are we?

Arithmetic is a company made up of people determined to improve the way acne is treated in adults. Our headquarters are in San Francisco and manufacturing takes place in the United States.

I've tried a lot of acne products and nothing worked. Why should I buy yours?

Our product is optimized to treat adult acne. Few others are are. We've studied the latest academic and clinical research to learn about new approaches that work for adults. Our chemists applied these evidence-based concepts to create an elegant and effective product. 

How fast does your product work?

Our product is powerful and in many cases it heals acne quickly. But it is not designed for fast results. Fast-acting acne products often work well for short-term acne on teen skin. For adult acne, products that can be used consistently over a longer period of time are often more effective.

Will your product cure my acne?

There is no sure-fire cure for acne. Our product is designed to prevent side effects acne products can cause, like dryness, flaking, pain, and skin irritation. With fewer side effects, adults can treat their acne more consistently over time. This unique approach aligns with recent research and may work better for many adults than conventional product.

My skin is oily. Is your product oil-free?

No, and here's why. We know it's counterintuitive, but some oils are good for skin, even oily skin. When you deprive your skin of hydration it forces your glands to pump more oil to your skin and that's not good for acne.

Our product contains moisturizing ingredients that counteract the drying effects of benzoyl peroxide and help acne-fighting ingredients penetrate more deeply into your skin.

What can I do to rebalance my oily skin?

We recommend that all skin types hydrate their skin with a moisturizer every time they wash their face. There are many excellent moisturizers on the market but two we like for acne-prone skin are CeraVe's Moisturizing Lotion AM (at drugstores) and Murad's Oil-Control Mattifier SPF 15 (at Sephora). We have no connection to either of these companies.

What is the texture of the product?

It's a luxuriously thick off-white cream.

What does your product smell like?

The product contains no added fragrance but it contains tea tree oil which imparts a mild, pleasant, and natural antiseptic scent.

Can teenagers use your product?

Absolutely. We developed our product to provide excellent long-term results for adults. But it works great for teens, too.

Is your product tested on animals? 

No. Our product is vegan, too (it contains no animal byproducts). 

Your prices are more than I usually spend on skincare products. Why is it expensive?

We're a small company that has invested a lot in research and development, extremely high quality ingredients, and free shipping. Many of our customers find our products a great value. One bottle of our Acne Control Complex often lasts several months, which is considerably less expensive than many prescription acne products or multi-step skincare systems. Still think it's expensive? Click here

How much should I use and how often?

See the Drug Facts for warnings and directions (enclosed with the product and on the product page). Generally, start with a sensitivity test by applying a very small amount of product on a small patch of skin 2-3 times per week. Products containing benzoyl peroxide should be used cautiously, even if you've used the ingredient in the past. Over time, you can build up to daily use.

I don't like benzoyl peroxide. Why is it in your product?

Benzoyl peroxide works extremely well (it's even better than many prescription drugs). If you've had a bad experience with a benzoyl peroxide product, chances are it was at a high dosage of 5-10%. Our product contains a low 3% dosage.

Lower dosages have been proven just as effective as higher dosages but with fewer side effects. Plus, half of our product's 12 ingredients are natural moisturizers, which help counter the side effects of benzoyl peroxide. Allergies to benzoyl peroxide are extremely rare but if you have one, do not use our product.

Does your product contain unhealthy ingredients? 

No. Our product contains no parabens, sulfates, synthetic fragrances, synthetic dyes, petrochemicals, phthalates, or triclosan.

The Skin Deep database from the Environmental Working Group rates benzoyl peroxide as having a low risk profile for health concerns including cancer, reproductive toxicology, and allergies. You can see their profile of benzoyl peroxide here. (The Environmental Working Group does not endorse any products or companies.)

How long does it take my order to ship?

We love fast, free shipping. Orders usually ship within one business day. Once your order has shipped, expect the following approximate transit times: 

  • Standard Shipping (Free): 3-7 Days 
  • Priority Shipping ($4): 2 Days
  • Expedited Shipping ($12): 1 Day

We may ship products by ground or air; our shipping speeds don't correspond to any carrier-branded shipping services. Orders sent to P.O. Boxes, Alaska, Hawaii, and Puerto Rico take longer. 

What is your guarantee and return policy?

If you’re not 100% satisfied with our product, we offer a no questions asked, 30-day returns from the day you receive your order. See our policy here.

Will you ship your product outside of the United States?

Not yet. Sign up for our e-mail list and we'll let you know when our products become available in your country.

Is my payment information secure? 

Yes. When you begin the checkout process, you will be transferred to a secure server. If you use a credit or debit card, the company that hosts our website and checkout process is Certified Level 1 PCI DSS compliant. Here's a link that explains what that means. If you use PayPal, you'll get the benefit of their security. Since our payments are handled by these other companies, our company never has access your credit card number or other payment information.