Last updated: 21 July 2026

The information on 420formulator.com is provided by Mike Harmon for educational and general informational purposes. I make reasonable efforts to provide useful and accurate information, but skincare formulation, aromatherapy, cannabis and individual health circumstances are complex subjects.

The information on this website is not a substitute for advice from an appropriately qualified medical, pharmaceutical, legal or other professional.

Medical and Health Information

Nothing on 420formulator is intended to diagnose, treat, cure or prevent any disease or medical condition. The website does not provide medical advice, individual treatment or personalised health recommendations.

Do not disregard professional medical advice or delay seeking it because of something you have read on this website.

If you are pregnant, breastfeeding, taking medication, living with a medical condition or preparing a product for someone who is medically vulnerable, consult an appropriately qualified healthcare professional before using cannabis, essential oils, herbs, supplements or other active ingredients.

Seek urgent medical help if you experience a serious or unexpected reaction.

My Background

My background includes completed training in professional aromatherapy, reflexology, iridology and colon hydrotherapy, together with further study in nutrition, complementary health and natural skincare.

I am now retired from clinical practice. I do not diagnose medical conditions, provide individual treatment or maintain professional practice registration or insurance.

My earlier training, formulation experience, personal experience and current research inform the educational content on 420formulator. They do not create a practitioner and patient relationship between me and anyone who uses this website.

Personal Experience and Research

Some articles include my personal experiences, observations and formulation preferences. These are identified as such where appropriate and should not be treated as clinical evidence or as a guarantee that another person will have the same experience.

Scientific understanding develops over time. Research discussed on 420formulator may be preliminary, laboratory based or limited in its application to people. A reference to research does not mean that an ingredient or formulation has been proven to treat a medical condition.

DIY Skincare and Formulation

Recipes and formulation information are provided as educational starting points. Ingredients can vary between suppliers, countries and batches. Substituting an ingredient, changing a percentage or altering the preparation method can affect a product’s texture, stability, safety and preservation.

Before making or using a formulation:

  • Check the supplier’s current safety information and documentation.
  • Follow appropriate hygiene and manufacturing practices.
  • Weigh ingredients accurately.
  • Observe recommended usage rates and dermal limits.
  • Use an appropriate broad-spectrum preservative in formulations that require one.
  • Conduct suitable stability, compatibility and microbial testing when appropriate.
  • Label and store the finished product safely.
  • Keep ingredients and finished products away from children and animals.

A preservative does not compensate for poor hygiene, unsuitable packaging or a badly designed formulation. Appearance and smell alone cannot confirm that a product is free from harmful microbial contamination.

Home recipes published on 420formulator have not necessarily undergone professional cosmetic safety assessment, challenge testing or laboratory stability testing. They must not be assumed suitable for commercial manufacture or sale.

Anyone placing cosmetic products on the market is responsible for meeting the laws and safety requirements that apply in the relevant country. A recipe appearing on this website does not constitute regulatory approval or a completed commercial formula.

Allergies, Sensitivities and Patch Testing

Natural ingredients can cause irritation, sensitisation or allergic reactions. Natural does not automatically mean safe or suitable for everyone.

Check the full composition and safety information for every ingredient. Where appropriate, test a small amount of the finished product on a limited area before wider use. Patch testing may reduce uncertainty, but it cannot guarantee that a reaction will not occur.

Do not use a product on broken, infected or severely irritated skin unless an appropriately qualified healthcare professional has advised you to do so. Stop using a product if irritation or another adverse reaction develops.

Essential Oils and Aromatic Ingredients

Essential oils are concentrated substances and must be used within appropriate limits. Do not apply an essential oil undiluted merely because it is described as natural.

Dermal limits differ between oils and may also depend upon their composition, oxidation, extraction method and intended use. Some expressed citrus oils can increase sensitivity to sunlight. Essential oils do not dissolve in water without a suitable dispersing or solubilising system.

Information on 420formulator about topical use does not constitute advice to ingest essential oils. Keep essential oils away from the eyes and other sensitive areas, and store them securely away from children and animals.

Cannabis Information

Cannabis laws vary between countries and between individual states, territories and local jurisdictions. In the United States, state permission does not necessarily mean that conduct is lawful under federal law. Readers must check all laws and restrictions that apply where they live before possessing, growing, preparing, purchasing or using cannabis or cannabis-derived ingredients.

Nothing on 420formulator should be interpreted as legal advice or as encouragement to break the law.

Cannabis potency and composition can vary considerably. Strain names, appearance and the quantity of plant material used do not reliably establish cannabinoid strength.

Homemade cannabis preparations have not been laboratory standardised. Calculations and suggested quantities can provide estimates, but they cannot guarantee the amount of THC, CBD or another cannabinoid in a finished product.

Some cannabis products may cause intoxication or other unwanted effects. Effects can be delayed and may last longer than expected, particularly with edible products. Begin cautiously, do not take more simply because an effect has not yet appeared, and never drive or operate machinery while impaired.

Cannabis products must be clearly labelled, stored securely and kept away from children, animals and anyone who could consume or use them unintentionally. Edibles should never be stored in a way that allows them to be mistaken for ordinary food.

If cannabis use causes severe or worrying symptoms, seek appropriate medical help.

420formulator contains links to websites and products operated or supplied by third parties. I choose links that I believe may be helpful, but I do not control third-party websites, product composition, availability, safety information, prices or business practices.

A link does not guarantee that a product will remain unchanged or be suitable for your circumstances. Check the seller’s current product information, ingredients, warnings, delivery terms and returns policy before purchasing or using anything.

Some links on 420formulator are affiliate links. I may receive a commission if you make a purchase through one of these links, at no additional cost to you.

I am the author of Off Your Face Creams and receive royalties from sales of the book. A link to the book may therefore represent my own commercial interest even when it is not an affiliate link.

Commercial relationships are explained more fully in the Disclosure Policy.

Accuracy and Availability

I make reasonable efforts to keep information accurate and useful. However, I cannot guarantee that every page will always be complete, current or free from error. Supplier specifications, research, laws, safety guidance and external websites can change after an article is published.

You should confirm important information through current and authoritative sources before relying upon it.

I may update, correct or remove content without notice. I do not guarantee that the website or any particular page will always remain available.

Responsibility for Use

You are responsible for deciding whether a recipe, ingredient, technique or product is appropriate for you and for using the information on 420formulator safely and lawfully.

To the fullest extent permitted by applicable law, I am not responsible for losses arising from reliance upon information on this website, the use or misuse of a formulation, undisclosed allergies, unauthorised substitutions, failure to follow safety instructions or the actions of third-party websites and suppliers.

Nothing in this Disclaimer excludes or restricts liability where doing so would be unlawful, including liability that cannot legally be excluded or limited under applicable consumer law.

Contact

If you believe that something on 420formulator is inaccurate, unsafe, outdated or improperly attributed, please contact me.