Insulin and Insulin Analogues: Medicine Overview
A plain-language class overview of human insulin and rapid- and long-acting insulin analogues, using FDA labels for Humalog, Lantus and Novolin R, with safety points and no dosing advice.
Content last updated . This page has not been medically reviewed.
Quick overview
Insulin medicines are a family, not a single product. This page explains the main types of insulin medicines using three FDA labels as examples. It is a class overview for education. It does not give dosing, does not compare products to pick one, and does not advise anyone to start, switch or stop an insulin. Those decisions belong to the person's prescriber.Evidence label used here: approved medicine. Each product named below is FDA-approved for diabetes, per its label. The three labels read are one for each type, not a full list of insulin brands.
Molecule, analogue, brand: keeping the words apart
- Human insulin is the label term for products such as Novolin R, which the label calls a short-acting human insulin. [1]
- Insulin analogue means a modified insulin. The Humalog label calls insulin lispro a "rapid acting human insulin analog." The Lantus label calls insulin glargine a "long-acting human insulin analog." [2][3]
- A brand (Humalog, Lantus, Novolin) is a product. The same molecule can have more than one brand, and strengths, pens and mixes differ by product. In the US, the FDA's biosimilar list includes insulin glargine and insulin aspart biosimilars, and one glargine product (Semglee) was described by the FDA as the first interchangeable biosimilar insulin. [4]
What insulin medicines do
Per the labels, the primary activity of insulin and its analogues is regulating glucose metabolism: they lower blood glucose by stimulating glucose uptake by skeletal muscle and fat and by inhibiting glucose production by the liver. [2][3][1]How the types differ
| Type (label example) | What the label says about timing |
|---|---|
| Rapid-acting analogue (Humalog, insulin lispro) | Equipotent to human insulin on a molar basis, with a more rapid onset and shorter duration than regular human insulin. [2] |
| Short-acting human insulin (Novolin R) | Glucose-lowering begins about 30 minutes after a subcutaneous injection, is greatest between 1.5 and 3.5 hours and ends around 8 hours. [1] |
| Long-acting analogue (Lantus, insulin glargine) | Slower, more prolonged absorption with no pronounced peak compared with NPH insulin; the median time to the end of effect was 24 hours versus 14.5 hours for NPH. [3] |
All three labels stress that the time course varies between people and within the same person. [2][3][1]
Trial evidence in the labels
- Humalog: studied in pediatric and adult type 1 diabetes (789 people) and adult type 2 diabetes (722 people). [2]
- Lantus: compared with NPH insulin in open-label, randomized trials of 2,327 adults and 349 children with type 1 diabetes and 1,563 adults with type 2 diabetes. In general the HbA1c reduction was similar to NPH. [3]
These are blood-sugar-control results against another insulin, not trials showing one insulin "better" for every person.
Special groups
For Humalog in pregnancy, published studies have not reported a link between insulin lispro and major birth defects, miscarriage or poor maternal or fetal outcomes, while poorly controlled diabetes in pregnancy carries risks to mother and baby. [2] The label also flags extra hypoglycemia monitoring with kidney or liver impairment and with hypoglycemia unawareness. [2]Monitoring and professional care
Labels tie insulin use to blood glucose monitoring, more frequent checks when anything changes (dose, other glucose-lowering drugs, meals, activity) and individualized plans. [2][3] For the wider picture, see Metabolic and Diabetes Peptide Medicines, Pramlintide (a separate hormone-based add-on to mealtime insulin) and Prediabetes, Type 2 Diabetes and Metabolic Syndrome.Off-label and investigational questions
Insulin products sold outside approved channels, and any use of insulin without diabetes, are not covered by these labels. Proper evidence not found in the three labels and the FDA list read. See Compounded and Unapproved GLP-1 Products for how regulators treat unapproved compounded peptide products.Frequently asked questions
Are all insulins the same?
No. The labels describe different timing for human regular insulin, a rapid-acting analogue and a long-acting analogue. [2][3][1]
What is an insulin analogue?
A modified form of insulin. The labels use the term for insulin lispro (rapid-acting) and insulin glargine (long-acting). [2][3]
What is a biosimilar insulin?
The FDA keeps a list of biosimilar products, including insulin glargine and insulin aspart versions of reference products, and calls one glargine product the first interchangeable biosimilar insulin. [4]
Can I switch from one insulin to another myself?
This page cannot advise that. The Humalog label says changes in type, brand or strength should be made under close medical supervision. [2]
Where is the main hub for approved peptide medicines?
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Approved use (United States)
All three labels give the same broad indication: to improve glycemic (blood glucose) control in adults and pediatric patients with diabetes mellitus. [2][3][1] The Lantus label adds a limit: it is not recommended for treating diabetic ketoacidosis. [3] Other countries were not verified for this page.
Major safety information
- Hypoglycemia is the most common adverse reaction. The Humalog label says severe hypoglycemia can cause seizures, can be life-threatening and can impair concentration and reaction time, including while driving. [2]
- Changes in regimen (strength, brand, type, injection site or method) can cause high or low blood sugar, so the label says they should be made under close medical supervision. [2]
- Medication mix-ups between insulin products can happen, and the label warns against moving a concentrated pen product into a syringe because severe overdose can result. [2]
- Other warnings: allergic reactions that can be life-threatening, low potassium, and fluid retention with heart failure when used with thiazolidinedione diabetes pills. [2]
- Never share pens or needles, even with a new needle, because of blood-borne infection risk. [2]
- Skin changes: repeated injections into areas of lipodystrophy or localized skin amyloidosis can cause high blood sugar, and a sudden move to an unaffected area has caused low blood sugar. [2]
- Both Humalog and Lantus are contraindicated during an episode of hypoglycemia and in people allergic to the product's ingredients. [2][3]
References
- NOVOLIN R (human insulin) injection, prescribing information (DailyMed label version dated 2022-11-23). Read 2026-10-22.
- HUMALOG (insulin lispro) injection, prescribing information (DailyMed label version dated 2026-06-16). Read 2026-10-22.
- LANTUS (insulin glargine) injection, prescribing information (DailyMed label version dated 2025-06-02). Read 2026-10-22.
- FDA, Biosimilar Product Information (list of approved biosimilar and interchangeable products). Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.